William james sidis



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PERPETUAL CALENDAR Filed Dec. 15, 1927 ed hu For1700or2l00 11521909 gg 511800115111902 a su" M0" Tue l F sa* Forum 413511111 22o MonTueWed ThuFn Sai Sun 1165-1199, 13s 1 Tue edTh Fri Sat SunMon 1833-1860, es e ,56]9001 B40 ed Thu Fn Sais o Tue 2013-2065, 112 ThuFm Sai SwnMor'Iue ed Forbeforel'IOO orufer 04' FFL Sai SlmMOn Tl ved Thil.

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Patented `inne 25, 1929.

UNITED STATES WILLIAM JAMES SIDIS,

SF NEW YORK, N. Y.

PERPETUAL CALENDAR.

Application filed Ieceinher 15, 1927.

The invention relates to perpetual calendars in which week-days can be found directly for any given date whatever; and its object is, first, to provide a means by which all such week-days can be looked up in a direct, simple, and easily underrt ndablc manner; secondly, to avoid the croK reference tables or complex mechanism, one or the other of which have hitherto generally been features of perpetual calencars providing means te look up the week-day of any given date whatever; thirdly, to provide a perpetual calendar in which, once the calendar is adjusted for any given year, a complete and condensed calendar for the year is at once plainly visible.

The accompanying vdrawing illustrates the invention, a complete front view of the twoslot arrangement being shown in Figurell; Figure 2 illustrates the back sheet or disk belonging to that form of the invention; while Figure 3 shows a front view of the left half of the indica-tor form of the invention, the arrangement of the right half being identical with that in Figure 1.

The essential features of the calendar are a top or front sheet (see Fig. 1) and a bottom or back sheet (see Fig. 2), in disk form, so pivot-ed at its center that it can rotate freely behind the front sheet. l

The said back sheet (see Fig. 2) consists of two concentric sections, the .month-section (1) and the year-section rlhe month-section (l) consists of 24, 25, or 26 sectors, each containing the name of a month or a set of such names. The first seven such sectors shall be filled in the following cyclical order: (a) October; (b) May; (c) February, August; (d) March, November; (e) June; (f) September, D ecember; (g) January, April, July. The six following sectors shall be a repetition of the first six sectors, and inthe same order. The last seven sectors shall be filled in the following cyclical order: February, March, November; June; (c) September, December; (d) April, July; (e) January, October; May; (g) August; while the siX sectors preceding these shall duplicate the last siX sectors, and in the same order. This provides a cyclical order for the first thirteen and for the last thirteen sectors, thus making 26 sectors possible; but, as in the illustration, as many as two sectors can be made common to the two classes, thus bring- Serial No. 240,214.

ing the total number of sectors down by one or two, to 25 or 24.

The year-section (2) shall consistl of a group of leap-years in seven sectors, to correspond with the firstv seven sectors of the month-section (1) and a group of nonleap-years (11) in seven sectors, to correspond to the first seven of the last thirteen sectors of said month-section. The angle between corresponding sectors in the yearsection and the inontli-section must be in all cases the same, to correspond to the angle on the front sheet between the initial edge of t/he year-slot (5) and that of the month-slot All the years-within a definite period (in this instance, 1900 to 1956) are placed in one of the fourteen sectors mentioned in the preceding paragraph, each such year being placed in the leap-year sectors or in the nonleap-year sectors according to whether it is or is not a leap-year; and each year being further placed in the sector corresponding to the months beginning in that year with the week-day (Sunday in the present instance) found in the first row and first column of the week-day group (7) on the front sheet.

The front sheet (see Fig. 1) of the calendar has two perforations, a month-slot (6) to slide .over the month-section (1) of the back sheet, equal in width to the monthsection, and with such length that just seven sectors of the mouth-section can be seen at once through the month-slot; also a yearslot whose size, shape, and position is su -h that just one sector of the year-section of the back sheet is visible through it, said sector to be the one corresponding to the first sector visible through the monthslot.

Upon the front sheet of the Vcalendar also is a group of week days (7) arranged in seven rows and seven columns so that in each row and in each column the seven days of the week appear in the cylical order in which they occui', and so that the seven rows shall be continuations of the seven sectors of the month-section to be visible through the month-slot (6); also a group of the numbers from 1 to 31 (8), occupying the continuation of the seven columns of the week-day group (7), the said numbers being lister in succession, row by row.

in addition., the front sheet of the calendar should contain a conversion-table (9) stating` hoW many years have to be added or subtracted in order to use the calendar for years not listed in the year-section (2) of the back sheet.

The year-section may he removed entirely from the back sheet, and the years he arranged in similar fashion (see Fig. 3) in a circle about the pivot (l0) as center, on the front sheet of the disk form. If the years are indicated in this manner7 an indicator (ll) firmly attached to the back sheet, and rotating with it, must he used to replace the year-slot The pivot (l0) furnishes a means by which the back sheet, may loe so adjusted that the year desired will appear through theyearsslot (the conversion-table to he used in the case of years not Within the period covered on the back sheet). lVhen this is done. the months appearing through the mdnth-slot, and the Week-days and datenumoers on the front sheet, will together constitute a complete and condensed calendar for the year in question; the Week-day for any given date being' that located in the .same row as the .month1 and in the same column as the day of the month. In case the indicator form shown in Fig. 3 is used, the calendar is to be so adjusted that the indicator points to the year desired,l after which the calendar is to be used in the same manner as above described in this paragraph.

I claim:

The combination, in a perpetual calendar, of a disk containing the months properly grouped in successive sectors; a front sheet With a perforation making seven of those sectors visible when the disk is properly adjusted behind it, and containing` years properly grouped in sectors continuous With those or in other sectors ofthe same circle, as Well as week-days grouped in seven roWs and seven columns the seven rows co-operating' with the seven month sectors7 and the numbers l to 3l arranged in a continuation of those columns; also a pivot at the center of the disk and fastened to the front sheet at the central point of the year-sectors, with an indicator attached to said pivot and rotating with the disk, which can be made at Will to point to any year listed on the front sheet.

VILLIAM JAMES SIDIS. 

